Propagate errors from api calls to caller.

This defines an ApiResult type, and a corresponding Error type which
wraps any errors that can be returned from underlying libs. Prevents
panics due to unwraps in the core api.

The main app still unwraps, and will panic on any error, though. Fix
that later.

4 files changed, 72 insertions, 14 deletions

diff --git a/src/api.rs b/src/api.rs
index c31ea8f..826eaf2 100644
--- a/src/api.rs
+++ b/src/api.rs
@@ -16,8 +16,16 @@
     along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-use reqwest;
+use reqwest::{
+    self,
+    header::{
+        HeaderMap,
+        HeaderValue,
+    },
+    Client,
+};
 use crate::station::{Station, StationContainer};
+use crate::error::ApiResult;
 
 const API_BASE: &'static str = "https://oslobysykkel.no/api/v1";
 
@@ -30,23 +38,23 @@ pub struct Api {
 }
 
 impl Api {
-    pub fn new(api_key: String) -> Api {
-        let mut hdrs = reqwest::header::HeaderMap::new();
-        hdrs.insert("client-identifier", reqwest::header::HeaderValue::from_str(&api_key).unwrap());
+    pub fn new(api_key: String) -> ApiResult<Api> {
+        let mut hdrs = HeaderMap::new();
+        hdrs.insert("client-identifier", HeaderValue::from_str(&api_key)?);
 
-        let client = reqwest::Client::builder()
+        let client = Client::builder()
             .default_headers(hdrs)
-            .build().unwrap();
+            .build()?;
 
-        Api { client }
+        Ok(Api { client })
     }
 
-    pub fn stations(&self) -> Vec<Station> {
+    pub fn stations(&self) -> ApiResult<Vec<Station>> {
         let response_json = self.client.get(&url_for("stations"))
-            .send().unwrap()
-            .text().unwrap();
+            .send()?
+            .text()?;
 
-        let v: StationContainer = serde_json::from_str(&response_json).unwrap();
-        v.stations
+        let v: StationContainer = serde_json::from_str(&response_json)?;
+        Ok(v.stations)
     }
 }
diff --git a/src/error.rs b/src/error.rs
new file mode 100644
index 0000000..ed17362
--- /dev/null
+++ b/src/error.rs
@@ -0,0 +1,49 @@
+/*
+    oslobike - find free bikes in Oslo.
+    Copyright (C) 2019  Harald Eilertsen <haraldei@anduin.net>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+/// Error type returned by api calls.
+///
+/// This type wraps any error that can be returned by the underlying
+/// libs used by the oslobike api.
+#[derive(Debug)]
+pub enum Error {
+    InvalidHeaderValue(reqwest::header::InvalidHeaderValue),
+    ReqwestError(reqwest::Error),
+    JsonError(serde_json::error::Error),
+}
+
+impl From<reqwest::header::InvalidHeaderValue> for Error {
+    fn from(err: reqwest::header::InvalidHeaderValue) -> Error {
+        Error::InvalidHeaderValue(err)
+    }
+}
+
+impl From<reqwest::Error> for Error {
+    fn from(err: reqwest::Error) -> Error {
+        Error::ReqwestError(err)
+    }
+}
+
+impl From<serde_json::error::Error> for Error {
+    fn from(err: serde_json::error::Error) -> Error {
+        Error::JsonError(err)
+    }
+}
+
+/// Result type for api calls.
+pub type ApiResult<T> = std::result::Result<T, Error>;
diff --git a/src/lib.rs b/src/lib.rs
index 1968e0a..c08c2cb 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -17,6 +17,7 @@
 */
 
 mod api;
+mod error;
 mod station;
 
 // Re export the important parts of the API
diff --git a/src/main.rs b/src/main.rs
index 733af84..53752c0 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -21,8 +21,8 @@ use oslobike;
 
 fn main() {
     let api_key = dotenv::var("OSLOBIKE_APIKEY").expect("No API key defined!");
-    let api = oslobike::Api::new(api_key);
-    for station in api.stations() {
+    let api = oslobike::Api::new(api_key).unwrap();
+    for station in api.stations().unwrap() {
         println!("{:>4} {}: {}",
             station.id,
             station.title,